WASHINGTON -- A former CIA interrogator said making an al-Qaida detainee think he was drowning worked in 2002, but he now regards "waterboarding" as torture.

In an interview with ABC News, retired agent John Kiriakou told of the capture of Abu Zubaydah in Pakistan and his role in interrogating him. Kiriakou said he repeatedly questioned Zubaydah, but was not present when he was strapped to a board with cellophane around his mouth and nose as water was pumped down his throat.

Kiriakou said agents told him Zubaydah "broke" after 35 seconds.

"From that day on, he answered every question," Kiriakou said. "The threat information he provided disrupted a number of attacks, maybe dozens of attacks."

The ex-agent said his opinion of the interrogation technique has shifted since.

"At the time, I felt that 'waterboarding' was something that we needed to do. And as time has passed ... I think I've changed my mind," he told ABC.

It emerged last week videotapes of the session were destroyed by the CIA in 2005, which agency Director Michael Hayden said was done to protect the identities of CIA agents who appear on them.

Closed congressional hearings are scheduled this week into the destruction of the tapes, the Washington Post reported.